1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
3
4// Package objc is a low-level pure Go objective-c runtime. This package is easy to use incorrectly, so it is best
5// to use a wrapper that provides the functionality you need in a safer way.
6package objc
7
8import (
9 "errors"
10 "fmt"
11 "math"
12 "reflect"
13 "regexp"
14 "runtime"
15 "slices"
16 stdstrings "strings"
17 "structs"
18 "unicode"
19 "unsafe"
20
21 "github.com/ebitengine/purego"
22 "github.com/ebitengine/purego/internal/strings"
23)
24
25var hostLayoutType = reflect.TypeFor[structs.HostLayout]()
26
27// TODO: support try/catch?
28// https://stackoverflow.com/questions/7062599/example-of-how-objective-cs-try-catch-implementation-is-executed-at-runtime
29var (
30 objc_msgSend_fn uintptr
31 objc_msgSend_stret_fn uintptr
32 objc_msgSend func(obj ID, cmd SEL, args ...any) ID
33 objc_msgSendSuper2_fn uintptr
34 objc_msgSendSuper2_stret_fn uintptr
35 objc_msgSendSuper2 func(super *objc_super, cmd SEL, args ...any) ID
36 objc_getClass func(name string) Class
37 objc_getProtocol func(name string) *Protocol
38 objc_allocateProtocol func(name string) *Protocol
39 objc_registerProtocol func(protocol *Protocol)
40 objc_allocateClassPair func(super Class, name string, extraBytes uintptr) Class
41 objc_registerClassPair func(class Class)
42 sel_registerName func(name string) SEL
43 class_getSuperclass func(class Class) Class
44 class_getInstanceVariable func(class Class, name string) Ivar
45 class_getInstanceSize func(class Class) uintptr
46 class_addMethod func(class Class, name SEL, imp IMP, types string) bool
47 class_addIvar func(class Class, name string, size uintptr, alignment uint8, types string) bool
48 class_addProtocol func(class Class, protocol *Protocol) bool
49 ivar_getOffset func(ivar Ivar) uintptr
50 ivar_getName func(ivar Ivar) string
51 object_getClass func(obj ID) Class
52 object_getIvar func(obj ID, ivar Ivar) ID
53 object_setIvar func(obj ID, ivar Ivar, value ID)
54 protocol_getName func(protocol *Protocol) string
55 protocol_isEqual func(p *Protocol, p2 *Protocol) bool
56 protocol_addMethodDescription func(p *Protocol, name SEL, types string, isRequiredMethod bool, isInstanceMethod bool)
57 protocol_copyMethodDescriptionList func(p *Protocol, isRequiredMethod bool, isInstanceMethod bool, outCount *uint32) *MethodDescription
58 protocol_copyProtocolList func(p *Protocol, outCount *uint32) **Protocol
59 protocol_copyPropertyList2 func(p *Protocol, outCount *uint32, isRequiredProperty, isInstanceProperty bool) *Property
60 protocol_addProtocol func(p *Protocol, p2 *Protocol)
61 protocol_addProperty func(p *Protocol, name string, attributes []PropertyAttribute, attributeCount uint32, isRequiredProperty bool, isInstanceProperty bool)
62 property_getName func(p Property) string
63 property_getAttributes func(p Property) string
64
65 free func(ptr unsafe.Pointer)
66 _Block_copy func(Block) Block
67 _Block_release func(Block)
68)
69
70func init() {
71 objc, err := purego.Dlopen("/usr/lib/libobjc.A.dylib", purego.RTLD_GLOBAL|purego.RTLD_NOW)
72 if err != nil {
73 panic(fmt.Errorf("objc: %w", err))
74 }
75 objc_msgSend_fn, err = purego.Dlsym(objc, "objc_msgSend")
76 if err != nil {
77 panic(fmt.Errorf("objc: %w", err))
78 }
79 if runtime.GOARCH == "amd64" {
80 objc_msgSend_stret_fn, err = purego.Dlsym(objc, "objc_msgSend_stret")
81 if err != nil {
82 panic(fmt.Errorf("objc: %w", err))
83 }
84 objc_msgSendSuper2_stret_fn, err = purego.Dlsym(objc, "objc_msgSendSuper2_stret")
85 if err != nil {
86 panic(fmt.Errorf("objc: %w", err))
87 }
88 }
89 purego.RegisterFunc(&objc_msgSend, objc_msgSend_fn)
90 objc_msgSendSuper2_fn, err = purego.Dlsym(objc, "objc_msgSendSuper2")
91 if err != nil {
92 panic(fmt.Errorf("objc: %w", err))
93 }
94 purego.RegisterFunc(&objc_msgSendSuper2, objc_msgSendSuper2_fn)
95 purego.RegisterLibFunc(&object_getClass, objc, "object_getClass")
96 purego.RegisterLibFunc(&objc_getClass, objc, "objc_getClass")
97 purego.RegisterLibFunc(&objc_getProtocol, objc, "objc_getProtocol")
98 purego.RegisterLibFunc(&objc_allocateProtocol, objc, "objc_allocateProtocol")
99 purego.RegisterLibFunc(&objc_registerProtocol, objc, "objc_registerProtocol")
100 purego.RegisterLibFunc(&objc_allocateClassPair, objc, "objc_allocateClassPair")
101 purego.RegisterLibFunc(&objc_registerClassPair, objc, "objc_registerClassPair")
102 purego.RegisterLibFunc(&sel_registerName, objc, "sel_registerName")
103 purego.RegisterLibFunc(&class_getSuperclass, objc, "class_getSuperclass")
104 purego.RegisterLibFunc(&class_getInstanceVariable, objc, "class_getInstanceVariable")
105 purego.RegisterLibFunc(&class_addMethod, objc, "class_addMethod")
106 purego.RegisterLibFunc(&class_addIvar, objc, "class_addIvar")
107 purego.RegisterLibFunc(&class_addProtocol, objc, "class_addProtocol")
108 purego.RegisterLibFunc(&class_getInstanceSize, objc, "class_getInstanceSize")
109 purego.RegisterLibFunc(&ivar_getOffset, objc, "ivar_getOffset")
110 purego.RegisterLibFunc(&ivar_getName, objc, "ivar_getName")
111 purego.RegisterLibFunc(&protocol_getName, objc, "protocol_getName")
112 purego.RegisterLibFunc(&protocol_isEqual, objc, "protocol_isEqual")
113 purego.RegisterLibFunc(&protocol_addMethodDescription, objc, "protocol_addMethodDescription")
114 purego.RegisterLibFunc(&protocol_copyMethodDescriptionList, objc, "protocol_copyMethodDescriptionList")
115 purego.RegisterLibFunc(&protocol_copyProtocolList, objc, "protocol_copyProtocolList")
116 purego.RegisterLibFunc(&protocol_addProtocol, objc, "protocol_addProtocol")
117 purego.RegisterLibFunc(&protocol_addProperty, objc, "protocol_addProperty")
118 purego.RegisterLibFunc(&protocol_copyPropertyList2, objc, "protocol_copyPropertyList2")
119 purego.RegisterLibFunc(&property_getName, objc, "property_getName")
120 purego.RegisterLibFunc(&property_getAttributes, objc, "property_getAttributes")
121 purego.RegisterLibFunc(&object_getIvar, objc, "object_getIvar")
122 purego.RegisterLibFunc(&object_setIvar, objc, "object_setIvar")
123 purego.RegisterLibFunc(&free, purego.RTLD_DEFAULT, "free")
124
125 purego.RegisterLibFunc(&_Block_copy, objc, "_Block_copy")
126 purego.RegisterLibFunc(&_Block_release, objc, "_Block_release")
127 theBlocksCache = newBlockCache()
128}
129
130// ID is an opaque pointer to some Objective-C object
131type ID uintptr
132
133// Class returns the class of the object.
134func (id ID) Class() Class {
135 return object_getClass(id)
136}
137
138// Send is a convenience method for sending messages to objects. This function takes a SEL
139// instead of a string since RegisterName grabs the global Objective-C lock. It is best to cache the result
140// of RegisterName.
141func (id ID) Send(sel SEL, args ...any) ID {
142 return objc_msgSend(id, sel, args...)
143}
144
145// GetIvar reads the value of an instance variable in an object.
146func (id ID) GetIvar(ivar Ivar) ID {
147 return object_getIvar(id, ivar)
148}
149
150// SetIvar sets the value of an instance variable in an object.
151func (id ID) SetIvar(ivar Ivar, value ID) {
152 object_setIvar(id, ivar, value)
153}
154
155// keep in sync with func.go
156const maxRegAllocStructSize = 16
157
158// Send is a convenience method for sending messages to objects that can return any type.
159// This function takes a SEL instead of a string since RegisterName grabs the global Objective-C lock.
160// It is best to cache the result of RegisterName.
161func Send[T any](id ID, sel SEL, args ...any) T {
162 var fn func(id ID, sel SEL, args ...any) T
163 var zero T
164 if runtime.GOARCH == "amd64" &&
165 reflect.ValueOf(zero).Kind() == reflect.Struct &&
166 reflect.ValueOf(zero).Type().Size() > maxRegAllocStructSize {
167 purego.RegisterFunc(&fn, objc_msgSend_stret_fn)
168 } else {
169 purego.RegisterFunc(&fn, objc_msgSend_fn)
170 }
171 return fn(id, sel, args...)
172}
173
174// objc_super data structure is generated by the Objective-C compiler when it encounters the super keyword
175// as the receiver of a message.
176//
177// [SendSuper] calls objc_msgSendSuper2 instead of objc_msgSendSuper. Unlike objc_msgSendSuper, which expects
178// the superclass to message, objc_msgSendSuper2 expects the current class and begins looking the method up
179// in its superclass by itself, so the receiver's own class is what belongs in superClass.
180type objc_super struct {
181 _ structs.HostLayout
182 receiver ID
183 superClass Class
184}
185
186// SendSuper is a convenience method for sending message to object's super. This function takes a SEL
187// instead of a string since RegisterName grabs the global Objective-C lock. It is best to cache the result
188// of RegisterName.
189func (id ID) SendSuper(sel SEL, args ...any) ID {
190 super := &objc_super{
191 receiver: id,
192 superClass: id.Class(),
193 }
194 return objc_msgSendSuper2(super, sel, args...)
195}
196
197// SendSuper is a convenience method for sending message to object's super that can return any type.
198// This function takes a SEL instead of a string since RegisterName grabs the global Objective-C lock.
199// It is best to cache the result of RegisterName.
200func SendSuper[T any](id ID, sel SEL, args ...any) T {
201 super := &objc_super{
202 receiver: id,
203 superClass: id.Class(),
204 }
205 var fn func(objcSuper *objc_super, sel SEL, args ...any) T
206 var zero T
207 if runtime.GOARCH == "amd64" &&
208 reflect.ValueOf(zero).Kind() == reflect.Struct &&
209 reflect.ValueOf(zero).Type().Size() > maxRegAllocStructSize {
210 purego.RegisterFunc(&fn, objc_msgSendSuper2_stret_fn)
211 } else {
212 purego.RegisterFunc(&fn, objc_msgSendSuper2_fn)
213 }
214 return fn(super, sel, args...)
215}
216
217// SEL is an opaque type that represents a method selector
218type SEL uintptr
219
220// RegisterName registers a method with the Objective-C runtime system, maps the method name to a selector,
221// and returns the selector value. This function grabs the global Objective-c lock. It is best to cache the
222// result of this function.
223func RegisterName(name string) SEL {
224 return sel_registerName(name)
225}
226
227// Class is an opaque type that represents an Objective-C class.
228type Class uintptr
229
230// GetClass returns the Class object for the named class, or nil if the class is not registered with the Objective-C runtime.
231func GetClass(name string) Class {
232 return objc_getClass(name)
233}
234
235// MethodDef represents the Go function and the selector that ObjC uses to access that function.
236type MethodDef struct {
237 Cmd SEL
238 Fn any
239}
240
241// IvarAttrib is the attribute that an ivar has. It affects if and which methods are automatically
242// generated when creating a class with RegisterClass. See [Apple Docs] for an understanding of these attributes.
243// The fields are still accessible using objc.GetIvar and objc.SetIvar regardless of the value of IvarAttrib.
244//
245// Take for example this Objective-C code:
246//
247// @property (readwrite) float value;
248//
249// In Go, the functions can be accessed as follows:
250//
251// var value = purego.Send[float32](id, purego.RegisterName("value"))
252// id.Send(purego.RegisterName("setValue:"), 3.46)
253//
254// [Apple Docs]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocProperties.html
255type IvarAttrib int
256
257const (
258 ReadOnly IvarAttrib = 1 << iota
259 ReadWrite
260)
261
262// FieldDef is a definition of a field to add to an Objective-C class.
263// The name of the field is what will be used to access it through the Ivar. If the type is bool
264// the name cannot start with `is` since a getter will be generated with the name `isBoolName`.
265// The name also cannot contain any spaces.
266// The type is the Go equivalent type of the Ivar.
267// Attribute determines if a getter and or setter method is generated for this field.
268type FieldDef struct {
269 Name string
270 Type reflect.Type
271 Attribute IvarAttrib
272}
273
274// ivarRegex checks to make sure the Ivar is correctly formatted
275var ivarRegex = regexp.MustCompile(`^[a-z_][a-zA-Z0-9_]*$`)
276
277// RegisterClass takes the name of the class to create, the superclass, a list of protocols this class
278// implements, a list of fields this class has and a list of methods. It returns the created class or an error
279// describing what went wrong.
280func RegisterClass(name string, superClass Class, protocols []*Protocol, ivars []FieldDef, methods []MethodDef) (Class, error) {
281 class := objc_allocateClassPair(superClass, name, 0)
282 if class == 0 {
283 return 0, fmt.Errorf("objc: failed to create class with name '%s'", name)
284 }
285 // Add Protocols
286 for _, p := range protocols {
287 if !class.AddProtocol(p) {
288 return 0, fmt.Errorf("objc: couldn't add Protocol %s", protocol_getName(p))
289 }
290 }
291 // Add exported methods based on the selectors returned from ClassDef(string) SEL
292 for idx, def := range methods {
293 imp, err := func() (imp IMP, err error) {
294 defer func() {
295 if r := recover(); r != nil {
296 err = fmt.Errorf("objc: failed to create IMP: %s", r)
297 }
298 }()
299 return NewIMP(def.Fn), nil
300 }()
301 if err != nil {
302 return 0, fmt.Errorf("objc: couldn't add Method at index %d: %w", idx, err)
303 }
304 encoding, err := encodeFunc(def.Fn)
305 if err != nil {
306 return 0, fmt.Errorf("objc: couldn't add Method at index %d: %w", idx, err)
307 }
308 if !class.AddMethod(def.Cmd, imp, encoding) {
309 return 0, fmt.Errorf("objc: couldn't add Method at index %d", idx)
310 }
311 }
312 // Add Ivars
313 for _, instVar := range ivars {
314 ivar := instVar
315 if !ivarRegex.MatchString(ivar.Name) {
316 return 0, fmt.Errorf("objc: Ivar must start with a lowercase letter and only contain ASCII letters and numbers: '%s'", ivar.Name)
317 }
318 size := ivar.Type.Size()
319 alignment := uint8(math.Log2(float64(ivar.Type.Align())))
320 enc, err := encodeType(ivar.Type, false)
321 if err != nil {
322 return 0, fmt.Errorf("objc: couldn't add Ivar %s: %w", ivar.Name, err)
323 }
324 if !class_addIvar(class, ivar.Name, size, alignment, enc) {
325 return 0, fmt.Errorf("objc: couldn't add Ivar %s", ivar.Name)
326 }
327 offset := class.InstanceVariable(ivar.Name).Offset()
328 switch ivar.Attribute {
329 case ReadWrite:
330 ty := reflect.FuncOf(
331 []reflect.Type{
332 reflect.TypeFor[ID](), reflect.TypeFor[SEL](), ivar.Type,
333 },
334 nil, false,
335 )
336 var encoding string
337 if encoding, err = encodeFunc(reflect.New(ty).Elem().Interface()); err != nil {
338 return 0, fmt.Errorf("objc: failed to create read method for '%s': %w", ivar.Name, err)
339 }
340 val := reflect.MakeFunc(ty, func(args []reflect.Value) (results []reflect.Value) {
341 // on entry the first and second arguments are ID and SEL followed by the value
342 if len(args) != 3 {
343 panic(fmt.Sprintf("objc: incorrect number of args. expected 3 got %d", len(args)))
344 }
345 // The following reflect code does the equivalent of this:
346 //
347 // ((*struct {
348 // Padding [offset]byte
349 // Value int
350 // })(unsafe.Pointer(args[0].Interface().(ID)))).v = 123
351 //
352 // However, since the type of the variable is unknown reflection is used to actually assign the value
353 id, ok := reflect.TypeAssert[ID](args[0])
354 if !ok {
355 panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
356 }
357 ptr := *(*unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
358 reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem().Set(args[2])
359 return nil
360 }).Interface()
361 // this code only works for ascii but that shouldn't be a problem
362 selector := "set" + string(unicode.ToUpper(rune(ivar.Name[0]))) + ivar.Name[1:] + ":\x00"
363 class.AddMethod(RegisterName(selector), NewIMP(val), encoding)
364 fallthrough // also implement the read method
365 case ReadOnly:
366 ty := reflect.FuncOf(
367 []reflect.Type{
368 reflect.TypeFor[ID](), reflect.TypeFor[SEL](),
369 },
370 []reflect.Type{ivar.Type}, false,
371 )
372 var encoding string
373 if encoding, err = encodeFunc(reflect.New(ty).Elem().Interface()); err != nil {
374 return 0, fmt.Errorf("objc: failed to create read method for '%s': %w", ivar.Name, err)
375 }
376 val := reflect.MakeFunc(ty, func(args []reflect.Value) (results []reflect.Value) {
377 // on entry the first and second arguments are ID and SEL
378 if len(args) != 2 {
379 panic(fmt.Sprintf("objc: incorrect number of args. expected 2 got %d", len(args)))
380 }
381 id, ok := reflect.TypeAssert[ID](args[0])
382 if !ok {
383 panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
384 }
385 ptr := *(*unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
386 // the variable is located at an offset from the id
387 return []reflect.Value{reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem()}
388 }).Interface()
389 if ivar.Type.Kind() == reflect.Bool {
390 // this code only works for ascii but that shouldn't be a problem
391 ivar.Name = "is" + string(unicode.ToUpper(rune(ivar.Name[0]))) + ivar.Name[1:]
392 }
393 class.AddMethod(RegisterName(ivar.Name), NewIMP(val), encoding)
394 default:
395 return 0, fmt.Errorf("objc: unknown Ivar Attribute (%d)", ivar.Attribute)
396 }
397 }
398 objc_registerClassPair(class)
399 return class, nil
400}
401
402const (
403 encId = "@"
404 encClass = "#"
405 encSelector = ":"
406 encChar = "c"
407 encUChar = "C"
408 encShort = "s"
409 encUShort = "S"
410 encInt = "i"
411 encUInt = "I"
412 encLongLong = "q"
413 encULongLong = "Q"
414 encFloat = "f"
415 encDouble = "d"
416 encBool = "B"
417 encVoid = "v"
418 encPtr = "^"
419 encCharPtr = "*"
420 encStructBegin = "{"
421 encStructEnd = "}"
422 encUnsafePtr = "^v"
423)
424
425// encodeType returns a string representing a type as if it was given to @encode(typ)
426// Source: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html#//apple_ref/doc/uid/TP40008048-CH100
427func encodeType(typ reflect.Type, insidePtr bool) (string, error) {
428 switch typ {
429 case reflect.TypeFor[Class]():
430 return encClass, nil
431 case reflect.TypeFor[ID](), reflect.TypeFor[Block]():
432 return encId, nil
433 case reflect.TypeFor[SEL]():
434 return encSelector, nil
435 }
436
437 kind := typ.Kind()
438 switch kind {
439 case reflect.Bool:
440 return encBool, nil
441 case reflect.Int:
442 return encLongLong, nil
443 case reflect.Int8:
444 return encChar, nil
445 case reflect.Int16:
446 return encShort, nil
447 case reflect.Int32:
448 return encInt, nil
449 case reflect.Int64:
450 return encLongLong, nil
451 case reflect.Uint:
452 return encULongLong, nil
453 case reflect.Uint8:
454 return encUChar, nil
455 case reflect.Uint16:
456 return encUShort, nil
457 case reflect.Uint32:
458 return encUInt, nil
459 case reflect.Uint64:
460 return encULongLong, nil
461 case reflect.Uintptr:
462 return encPtr, nil
463 case reflect.Float32:
464 return encFloat, nil
465 case reflect.Float64:
466 return encDouble, nil
467 case reflect.Pointer:
468 enc, err := encodeType(typ.Elem(), true)
469 return encPtr + enc, err
470 case reflect.Struct:
471 if insidePtr {
472 return encStructBegin + typ.Name() + encStructEnd, nil
473 }
474 var encoding stdstrings.Builder
475 encoding.WriteString(encStructBegin)
476 encoding.WriteString(typ.Name())
477 encoding.WriteString("=")
478 for i := range typ.NumField() {
479 f := typ.Field(i)
480 if f.Type.ConvertibleTo(hostLayoutType) {
481 // The structs.HostLayout marker is a signal to the Go compiler
482 // with no counterpart in C, so it is not a member as far as
483 // @encode is concerned. Other zero-sized fields are: clang
484 // encodes a zero-length array member as [0c].
485 continue
486 }
487 tmp, err := encodeType(f.Type, false)
488 if err != nil {
489 return "", err
490 }
491 encoding.WriteString(tmp)
492 }
493 encoding.WriteString(encStructEnd)
494 return encoding.String(), nil
495 case reflect.UnsafePointer:
496 return encUnsafePtr, nil
497 case reflect.String:
498 return encCharPtr, nil
499 }
500
501 return "", errors.New(fmt.Sprintf("unhandled/invalid kind %v typed %v", kind, typ))
502}
503
504// encodeFunc returns a functions type as if it was given to @encode(fn)
505func encodeFunc(fn any) (string, error) {
506 typ := reflect.TypeOf(fn)
507 if typ.Kind() != reflect.Func {
508 return "", errors.New("not a func")
509 }
510
511 var encoding stdstrings.Builder
512 switch typ.NumOut() {
513 case 0:
514 encoding.WriteString(encVoid)
515 case 1:
516 tmp, err := encodeType(typ.Out(0), false)
517 if err != nil {
518 return "", err
519 }
520 encoding.WriteString(tmp)
521 default:
522 return "", errors.New("too many output parameters")
523 }
524
525 if typ.NumIn() < 2 {
526 return "", errors.New("func doesn't take ID and SEL as its first two parameters")
527 }
528
529 encoding.WriteString(encId)
530
531 for i := 1; i < typ.NumIn(); i++ {
532 tmp, err := encodeType(typ.In(i), false)
533 if err != nil {
534 return "", err
535 }
536 encoding.WriteString(tmp)
537 }
538 return encoding.String(), nil
539}
540
541// SuperClass returns the superclass of a class.
542// You should usually use NSObject‘s superclass method instead of this function.
543func (c Class) SuperClass() Class {
544 return class_getSuperclass(c)
545}
546
547// AddMethod adds a new method to a class with a given name and implementation.
548// The types argument is a string containing the mapping of parameters and return type.
549// Since the function must take at least two arguments—self and _cmd, the second and third
550// characters must be “@:” (the first character is the return type).
551func (c Class) AddMethod(name SEL, imp IMP, types string) bool {
552 return class_addMethod(c, name, imp, types)
553}
554
555// AddProtocol adds a protocol to a class.
556// Returns true if the protocol was added successfully, otherwise false (for example,
557// the class already conforms to that protocol).
558func (c Class) AddProtocol(protocol *Protocol) bool {
559 return class_addProtocol(c, protocol)
560}
561
562// InstanceSize returns the size in bytes of instances of the class or 0 if cls is nil
563func (c Class) InstanceSize() uintptr {
564 return class_getInstanceSize(c)
565}
566
567// InstanceVariable returns an Ivar data structure containing information about the instance variable specified by name.
568func (c Class) InstanceVariable(name string) Ivar {
569 return class_getInstanceVariable(c, name)
570}
571
572// Ivar an opaque type that represents an instance variable.
573type Ivar uintptr
574
575// Offset returns the offset of an instance variable that can be used to assign and read the Ivar's value.
576//
577// For instance variables of type ID or other object types, call Ivar and SetIvar instead
578// of using this offset to access the instance variable data directly.
579func (i Ivar) Offset() uintptr {
580 return ivar_getOffset(i)
581}
582
583func (i Ivar) Name() string {
584 return ivar_getName(i)
585}
586
587// MethodDescription holds the name and type definition of a method.
588// It matches the Objective-C runtime's struct objc_method_description.
589type MethodDescription struct {
590 _ structs.HostLayout
591 name, types uintptr
592}
593
594// Name returns the name of this method.
595func (m MethodDescription) Name() string {
596 return strings.GoString(m.name)
597}
598
599// Types returns the OBJC runtime encoded type description.
600func (m MethodDescription) Types() string {
601 return strings.GoString(m.types)
602}
603
604// PropertyAttribute contains the null-terminated Name and Value pair of a Properties internal description.
605// It matches the Objective-C runtime's objc_property_attribute_t.
606type PropertyAttribute struct {
607 _ structs.HostLayout
608 Name, Value *byte
609}
610
611// Property is an opaque type for Objective-C property metadata.
612type Property uintptr
613
614// Name returns the name of this property.
615func (p Property) Name() string {
616 return property_getName(p)
617}
618
619// Attributes returns a comma separated list of PropertyAttribute
620func (p Property) Attributes() string {
621 return property_getAttributes(p)
622}
623
624// Protocol is a type that declares methods that can be implemented by any class.
625type Protocol [0]func()
626
627// GetProtocol returns the protocol for the given name or nil if there is no protocol by that name.
628func GetProtocol(name string) *Protocol {
629 return objc_getProtocol(name)
630}
631
632// AllocateProtocol creates a new protocol in the OBJC runtime or nil if the protocol already exists.
633func AllocateProtocol(name string) *Protocol {
634 return objc_allocateProtocol(name)
635}
636
637// Register registers the protocol created using AllocateProtocol with the runtime. This must be done
638// before it is used anywhere and can only be called once.
639func (p *Protocol) Register() {
640 objc_registerProtocol(p)
641}
642
643// CopyMethodDescriptionList returns a list of methods that this protocol has given it isRequiredMethod and isInstanceMethod.
644func (p *Protocol) CopyMethodDescriptionList(isRequiredMethod, isInstanceMethod bool) []MethodDescription {
645 count := uint32(0)
646 desc := protocol_copyMethodDescriptionList(p, isRequiredMethod, isInstanceMethod, &count)
647 methods := slices.Clone(unsafe.Slice(desc, count))
648 free(unsafe.Pointer(desc))
649 return methods
650}
651
652// CopyProtocolList returns a list of the protocols that this protocol inherits from.
653func (p *Protocol) CopyProtocolList() []*Protocol {
654 count := uint32(0)
655 desc := protocol_copyProtocolList(p, &count)
656 protocols := slices.Clone(unsafe.Slice(desc, count))
657 free(unsafe.Pointer(desc))
658 return protocols
659}
660
661// CopyPropertyList returns a list of properties that this protocol has given it isRequiredProperty and isInstanceProperty.
662func (p *Protocol) CopyPropertyList(isRequiredProperty, isInstanceProperty bool) []Property {
663 count := uint32(0)
664 desc := protocol_copyPropertyList2(p, &count, isRequiredProperty, isInstanceProperty)
665 protocols := slices.Clone(unsafe.Slice(desc, count))
666 free(unsafe.Pointer(desc))
667 return protocols
668}
669
670// Name returns the name of this protocol.
671func (p *Protocol) Name() string {
672 return protocol_getName(p)
673}
674
675// Equals return true if the two protocols are the same.
676func (p *Protocol) Equals(p2 *Protocol) bool {
677 return protocol_isEqual(p, p2)
678}
679
680// AddMethodDescription adds a method to a protocol. This can only be called between AllocateProtocol and Protocol.Register.
681func (p *Protocol) AddMethodDescription(name SEL, types string, isRequiredMethod, isInstanceMethod bool) {
682 protocol_addMethodDescription(p, name, types, isRequiredMethod, isInstanceMethod)
683}
684
685// AddProtocol marks the protocol as inheriting from another. This can only be called between AllocateProtocol and Protocol.Register.
686func (p *Protocol) AddProtocol(protocol *Protocol) {
687 protocol_addProtocol(p, protocol)
688}
689
690// AddProperty adds a property to the protocol. This can only be called between AllocateProtocol and Protocol.Register.
691func (p *Protocol) AddProperty(name string, attributes []PropertyAttribute, isRequiredProperty, isInstanceProperty bool) {
692 protocol_addProperty(p, name, attributes, uint32(len(attributes)), isRequiredProperty, isInstanceProperty)
693}
694
695// IMP is a function pointer that can be called by Objective-C code.
696type IMP uintptr
697
698// NewIMP takes a Go function that takes (ID, SEL) as its first two arguments.
699// It returns an IMP function pointer that can be called by Objective-C code.
700// The function panics if an error occurs.
701// The function pointer is never deallocated.
702func NewIMP(fn any) IMP {
703 ty := reflect.TypeOf(fn)
704 if ty.Kind() != reflect.Func {
705 panic("objc: not a function")
706 }
707 // IMP is stricter than a normal callback
708 // id (*IMP)(id, SEL, ...)
709 switch {
710 case ty.NumIn() < 2:
711 fallthrough
712 case ty.In(0) != reflect.TypeFor[ID]():
713 fallthrough
714 case ty.In(1) != reflect.TypeFor[SEL]():
715 panic("objc: NewIMP must take a (id, SEL) as its first two arguments; got " + ty.String())
716 }
717 return IMP(purego.NewCallback(fn))
718}